1. Field of the Invention
This invention relates to a shaft coupling allowing for an offset of axes, which coupling comprises radially displaceable members and preferably serves to couple a journal of a printing cylinder to a drive shaft and comprises positively interengaging coupling parts, which are connected to the respective shafts to be coupled, and means for forcing said coupling parts against each other.
2. Description of the Prior Art
Couplings of that kind are used when an offset of the axes of the shafts which are to be coupled cannot be avoided. In multicolor printing presses the printing cylinders of the several printing units are driven by drive shafts and each drive shaft is connected to a journal of a printing cylinder by a shaft coupling, which allows for an offset of the axes of the drive shaft and of the journal of the printing cylinder because that offset of the axes can never entirely be avoided. Such couplings are known in the form of so-called Oldham couplings. For instance, a six-color printing press may be used to print with only four rather than six colors. In that case the two printing cylinders which are not required for the printing operation are uncoupled from the associated drives but the associated drive shafts provided with the coupling parts which are mounted thereon and allow for an offset of axes are still operated. When the coupling part which allows for an offset of the associated printing cylinder the radially displaceable members of that coupling part will undesirably be radially outwardly displaced so that an undesired rotary unbalance will occur and will result not only in substantial loads on the bearings for the drive shaft but also in an unsteady operation of the printing press.